Examining the Potential of Forest Residue-Based Amendments for Post-Wildfire Rehabilitation in Colorado, USA

Abstract

Wildfire is a natural disturbance, though elemental losses and changes that occur during combustion and post-fire erosion can have long-term impacts on soil properties, ecosystem productivity, and watershed condition. Here we evaluate the potential of forest residue-based materials to rehabilitate burned soils. We compare soil nutrient and water availability, and plant recovery after application of 37 t ha−1 of wood mulch, 20 t ha−1 of biochar, and the combination of the two amendments with untreated, burned soils. We also conducted a greenhouse trial to examine how biochar influenced soil nutrient and water content under two wetting regimes. The effects of wood mulch on plant-available soil N and water content were significant and seasonally consistent during the three-year field study. Biochar applied alone had few effects under field conditions, but significantly increased soil pH, Ca, P, and water in the greenhouse. The mulched biochar treatment had the greatest effects on soil N and water availability and increased cover of the most abundant native plant. We found that rehabilitation treatments consisting of forest residue-based products have potential to enhance soil N and water dynamics and plant recovery following severe wildfire and may be justified where erosion risk or water supply protection are crucial.

Ecological and genomic responses of soil microbiomes to high-severity wildfire: linking community assembly to functional potential

“…As such, future studies should investigate how management of post-fire soils can create conditions leading to the recovery of beneficial microbes (e.g., N-fixing bacteria, mycorrhizal fungi), such as the rapid re-establishment of the native plant community. In certain circumstances, broadcast mulch additions [ 75 ] may be useful to alleviate C limitation and drought stress on the microbial community, leading to increased microbial resilience and N stability [ 44 ]. However, assisted colonization of microbial inoculants may be, in most cases, unnecessary, as dispersal limitation played only a minor role in prokaryote recovery.…”

Biochar Production and Application in Forest Soils-A Critical Review

“…Application of biochar at a high rate (50-100 t ha -1 ) increased soil pH from 4 to 4.8 in Eucalyptus forestry plantation [117]. Later, Rhoades et al [118] also noted an increase in pH from 5.7 to 6.4 in lodgepole pine (Pinus contorta) forest soil under the joint application of biochar and mulch. Brady and Weil [119] claimed that biochar has a low bulk density; that can reduce the overall total bulk density of the soil after application.…”

Role of biochar on soil fertility improvement and greenhouse gases sequestration

“…Similarly, Ouyang et al 27 revealed that the amending of dairy manure biochar to the soil significantly promoted the formation of aggregates in both silty-clay and sandy-loam textured soils. Where: PV pore volume and SA surface area Soil pH: Increased soil pH as a result of biochar application has been extensively investigated in agricultural soils 15 and Rhoades et al 28 also reported that the combined application of biochar with rate of (20tha -1 ) and mulch (37 t ha -1 ) increased soil pH from 5.7 to 6.4 in forest soil.…”